Emperor Taizong of Liao (25 November 902 – 18 May 947), personal name Yaogu, sinicised name Yelü Deguang, courtesy name Dejin, was the second emperor of the Khitan-led Liao dynasty of China.
Background Yelü Deguang was born in 902, before the founding of the Liao dynasty. His father was the Yelü clan chieftain Yelü Abaoji, and his mother was Yelü Abaoji's wife Shulü Ping; he was their second son. As a young adult, he was described by the History of Liao as serious in his appearance and kind in his disposition, and often participating in his parents' governance of the state.History of Liao, vol. 3.
In 922, by which time Yelü Abaoji was the emperor of the Liao dynasty, Yelü Deguang was given the title of Generalissimo of All Forces (天下兵馬大元帥, Tianxia Bingma Da Yuanshuai), and he was put in charge of commanding incursions into the territory of Khitan's southern neighbor Former Jin. In 923, under him, Liao forces captured Jin's Ping Prefecture (平州, in modern Qinhuangdao, Hebei), and also defeated the Huxun Tribe (胡遜) of the Xi. It was said that he later followed Emperor Taizu in defeating the Khitan Jueli Tribes (厥里), forcing the submission of the Dangxiang tribes in the Ordos Loop region, conquering the garrisons of the Hexi Corridor region, capturing the capital of the Gansu Uyghur Kingdom, defeating Balhae, and destroying the Dalugu Tribes (達盧骨).
In 926, Emperor Taizu decided to conquer Balhae. In a campaign, he captured the important Balhae city Fuyu (夫餘, in modern Siping, Jilin).Zizhi Tongjian, vol. 275. (This appeared to have ended the Balhae state, even though Emperor Taizu did not at this time capture Balhae's capital Longquan.)Bo Yang Edition of the Zizhi Tongjian, vol. 68 . Emperor Taizu set up a Dongdan Kingdom over the old Balhae territory, with its capital at Fuyu, and made Yelü Deguang's older brother Yelü Bei its king, with the title of "Imperial King of Man" (人皇王, Ren Huangwang), echoing the titles used by himself ("Imperial Emperor of Heaven," 天皇帝, Tian Huangdi) and his wife (Yelü Bei's mother) Empress Shulü ("Imperial Empress of Earth," 地皇后, Di Huanghou). He gave Yelü Deguang the title of "Generalissimo Crown Prince" and made Yelü Deguang in charge of the Liao capital Linhuang (臨潢), which Yelü Bei had previously been in charge of.
Shortly after conquering Fuyu, however, Emperor Taizu fell ill and died while still at Fuyu. Empress Shulü took over effective leadership of the Liao dynasty, and she and Yelü Bei began the trek of escorting Emperor Taizu's casket back to Linhuang, leaving one of Emperor Taizu's younger brother Yelü Anduan (耶律安端) temporarily in charge at Dongdan. Once then returned to Linhuang, she wanted to divert the succession away from Yelü Bei, as she had favored Yelü Deguang. However, formally, she called an assembly of the chieftains, along with Yelü Bei and Yelü Deguang, and stated to them, "I love both of my sons, and I do not know which one to make emperor. You can decide which one you wish to support by holding his rein." The chieftains, knowing that she favored Yelü Deguang, rushed to him and held to his rein. She thereafter declared him emperor (as Emperor Taizong). Yelü Bei, angry over this turn of events, took several hundred soldiers and wanted to flee to Later Tang (Jin's successor state), but was intercepted by Liao border guards. Empress Shulü did not punish him, but sent him to Dongdan.The History of Liao gave an account where it was Yelü Bei who voluntarily yielded the throne to Emperor Taizong, but that would appear to be inconsistent with his subsequent actions. See History of Liao, vol. 72.
Initial years of reign Emperor Taizong honored his mother Empress Shulü as empress dowager, and created his wife Lady Xiao Wen, who was a niece of Empress Shulü's, empress. It was said that he was filially pious toward his mother, such that if the empress dowager were ill and unable to eat, he would also not eat, and that if his mother were displeased at him, he would not dare to meet her until her temper had been soothed.
In 930, Emperor Taizong created his younger brother Yelü Lihu crown prince. Later in the year, apparently in reaction to being bypassed again, Yelü Bei fled from Dongdan to Khitan's southern neighbor Later Tang (Jin's successor state).Zizhi Tongjian, vol. 277.
In 935, Empress Xiao, after giving birth to her and Emperor Taizong's second son Yelü Yansage (耶律罨撒葛), fell ill and died. There would not be another empress during the rest of Emperor Taizong's reign.History of Liao, vol. 71.
Overlordship over Later Jin
During Later Jin's establishment As of 936, Later Tang was embroiled in internal strife, as then-emperor Li Congke was suspicious that his brother-in-law Shi Jingtang the military governor (Jiedushi) of Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi), would rebel against him. At the advice of the imperial scholars Li Song and Lü Qi (呂琦), Li Congke considered entering an alliance with the Khitan to ward off the possibility that Shi would seek aid from Khitan. However, when another imperial scholar, Xue Wenyu (薛文遇), argued against it by predicting that Emperor Taizong would demand a marriage alliance, Li Congke changed his mind and never made the alliance proposal.Zizhi Tongjian, vol. 280.
Not long after, in summer 936, Li Congke, under Xue's suggestion, issued an edict moving Shi from Hedong to Tianping Circuit (天平, headquartered in modern Tai'an, Shandong). This caused Shi to fear that he would be executed if he left Hedong, and so he rebelled. With Li Congke then sending an army, commanded by Zhang Jingda, to attack Hedong, Shi sent emissaries to Khitan to request aid, promising that, if Emperor Taizong would support him as the emperor of China, to serve Emperor Taizong as a father and to cede Lulong Circuit (盧龍, headquartered in modern Beijing) and Hedong's prefectures north of the Yanmen Pass to Khitan. When Shi's emissaries arrived at the Khitan court, Emperor Taizong was pleased, and he stated to Empress Dowager Shulü, "Your son had dreamt that Master Shi would be sending messengers here. Now it has happened. This was the will of heaven." He sent a reply that he would lead his entire empire's forces to aid Shi in the fall.
Meanwhile, Zhang put Hedong's capital Taiyuan under siege. Taiyuan was running low on food supplies, but its defenses held. In late fall, Emperor Taizong himself commanded 50,000 cavalry soldiers (but claimed publicly that it was 300,000) and headed for Taiyuan. When he arrived at Taiyuan's outskirts, Shi urged caution and not immediate engagement, but Emperor Taizong did not listen. Rather, he engaged Zhang's army immediately, crushing it and lifting the siege on Taiyuan. The remnants of Zhang's army took up position at Jin'an Base (晉安寨), near Taiyuan, but the combined Khitan/Hedong forces then put it under siege. While continuing to siege the Later Tang forces at Jin'an, Emperor Taizong created Shi emperor, having his state known as Jin (referred to by later historians as Later Jin. As part of Shi's enthronement announcement, he announced the agreement to cede Lulong and parts of Hedong, for a total of 16 prefectures, to Khitan, as well as to submit a large amount of silk each year as tribute.
Li Congke ordered Zhao Dejun the military governor of Lulong to command another army to rescue Zhang at Jin'an, but Zhao himself wanted Emperor Taizong's support to be emperor of China, and therefore halted some distance away at Tuanbo Valley (團柏谷, in modern Jinzhong, Shanxi), while he sent secret emissaries to Emperor Taizong's camp, negotiating with him. Zhao, who submitted bribes of gold and silk to Emperor Taizong, promised the terms of being fraternal states with Khitan and that Shi would be allowed to retain Hedong. As Zhao's army was still a strong one, Emperor Taizong was enticed. Shi, hearing of this, sent his close advisor Sang Weihan to plead with Emperor Taizong, arguing that the Khitan/Later Jin forces would prevail and that he should not turn his back on Shi. Emperor Taizong, after consideration, agreed with Sang and rejected Zhao's overture.
After Jin'an had been under siege for three months and ran out of supplies, Zhang's deputy Yang Guangyuan assassinated Zhang and surrendered the remaining Later Tang army, which Emperor Taizong turned over to Shi. Then they began to march toward the Later Tang capital Luoyang. With Yang having surrendered, Zhao's army lost its morale and also collapsed, and Zhao surrendered. At that time, Li Congke, who had himself led another Later Tang relief force northward, decided to return to Luoyang, but once he returned to Luoyang saw that the morale was crumbling and that many more generals were already surrendering to the combined Khitan/Later Jin forces. Emperor Taizong escorted Shi to Lu Prefecture (潞州, in modern Changzhi, Shanxi), and then, citing his belief that the Han Chinese would panic if Khitan forces actually arrived at Luoyang, stayed at Lu while Shi approached Luoyang. Li Congke, finding the situation hopeless, committed suicide with his family. Prior to the suicide, he had Emperor Taizong's older brother Yelü Bei executed. Shi entered Luoyang and established his authority there. He had Yelü Bei's casket escorted with honor back to Khitan.
After Later Jin's takeover of central China Emperor Taizong returned to Khitan proper with a number of Later Tang generals that he had detained. He also established Lulong's capital You Prefecture (幽州) as the southern capital, to facilitate the governance of the newly received 16 prefectures. He respected the captured official Zhang Li and listened to much of Zhang's advice.Zizhi Tongjian, vol. 281.
In 937, Xu Gao, the regent of Later Jin's southeastern neighbor Wu sent an emissary to Khitan to try to establish friendly relations. Emperor Taizong also sent an emissary to Wu in return. Later in the year, Emperor Taizong changed the name of his state from Khitan to Liao. He modeled his government after Chinese states', and made Zhao Dejun's son Zhao Yanshou a chief of staff (Shumishi) and chancellor. Later, after Xu seized the Wu throne and established Southern Tang as its emperor, he continued friendly relations with Liao, but on one occasion decided to assassinate the Liao emissary once the Liao emissary crossed into Later Jin territory, hoping to blame Later Jin for the assassination and disrupt Liao and Later Jin relations.
Meanwhile, Shi Jingtang, as Later Jin's emperor, continued to be very submissive to Liao. In 938, he offered honorific titles to Emperor Taizong and Empress Dowager Shulü, and sent his senior officials Feng Dao and Liu Xu to the Liao court to officially present the titles. During Shi's reign as Later Jin's emperor, he referred to himself as "subject" and "son," while referring to Emperor Taizong as "father emperor." Whenever Emperor Taizong issued edicts to him, he would receive them in a side hall rather than his own imperial hall, to show respect. Whenever at the Liao emperor's and empress dowager's birthdays or the deaths of key Liao officials, he would often present gifts, including also to Empress Dowager Shulü, Yelü Lihu, Yelü Anduan, the two chancellors in charge of Liao's southern and northern branches of government, and key Han officials such as Zhao Yanshou and Han Yanhui. Further, even when Emperor Taizong sent arrogantly-worded edicts, Shi would respond meekly. Therefore, throughout Shi's reign, there would be no disputes between Liao and Later Jin.